The present invention relates to rotatable cutting tools and, more specifically, to visual warnings for indicating that rotatable cutting tools are operating.
Rotatable cutting tools are well known and include, among others, saw blades, cutterheads or chucks, or the like, with insertable blades, drill bits, router bits, and the like. These tools are used for cutting a variety of solid materials, and often at least part of the cutting tool is exposed and creates a potential hazard during cutting operations. Operators or others near the cutting tool may not take notice of the cutting tool and may not easily recognize that the cutting tool is rotating. This can result in property damage and injuries to humans.
Lights or sounds are often used as warning mechanisms to reduce the risk of inadvertent contact with the sharp cutting edges of rotating cutting tools. However, due in part to the busy or noisy environment where cutting tools are used, these warning mechanisms may be insufficient to avert accidents. One critical reason for their insufficiency is that they can be characterized as not being in sufficiently close association with the sharp edges of the cutting tools. This deficiency can become more critical in a shop where multiple cutting tools are in use, because workers may be contemporaneously exposed to warning lights and noises that are loosely associated with several machines. Worker complacency and fatigue may also increase the danger. Even under good environmental conditions, in a clean and quiet atmosphere, accidents involving cutting tools are virtually inevitable.
Thus, there exists a need for a visual warning that provides an improved indication of whether a cutting tool is rotating or stopped.
In accordance with one aspect of the present invention, a visual warning is provided that is in sufficiently close association with sharp edge(s) of a cutting tool, preferably by being on the cutting tool in close proximity to the sharp edges, so that the visual warning seeks to unambiguously indicate to someone in close proximity to the cutting tool whether the cutting tool is moving, and most preferably whether the cutting tool is rotating. In accordance with this aspect, multiple different colors are positioned on different portions of the surface of the cutting tool, and the portions are arranged such that they follow the same path when the cutting tool is rotated. When the cutting tool is stationary, the colors are separately discemable, but when the tool is rotated at a sufficient speed, the colors appear to blend to form a different, apparent color, which preferably serves as an annular, monochromatic, visual warning. Optionally, multiple of such visuals warnings, which are similarly or differently colored, can be provided on a single cutting tool.
In accordance with one aspect of the present invention, the colors of the colored portions are selected from a group consisting of primary colors. In accordance with a specific example of this aspect, the colors of the colored portions consist essentially of red and yellow, so that the apparent color is orange.
According to one aspect of the present invention, the cutting tool has a recess on its surface and the colors are disposed at least partially in the recess. By virtue of the recess, the colors can be flush with the surface or recessed with respect to the surface, so that the colors are not exposed to the harshest conditions that are in the vicinity of the operating cutting edge(s) of the cutting tool. For example, the colors avoid some of the physical abrasion that occurs between the cutting tool and the solid material that is cut by the cutting tool. This advantageously allows the colors to be at least somewhat protected while being in close proximity to the cutting edge(s), where the colors advantageously function as a visual warning that is closely associated with the danger that is intended to be avoided. That is, in accordance with this aspect, the recess preferably serves to allow the colors to be positioned in a location that is at least partially protected from substances that are proximate the one or more cutting edges of the tool and might have a tendency to remove the colors. This advantageously allows the colors to be positioned in close proximity to the cutting edges, which is where the colors will most effectively function as a visual warning in some scenarios.
In accordance with one aspect of the present invention, the differently colored portions of the cutting tool, which serve as the visual warning when the tool is rotated above a predetermined speed, are positioned radially outward from a shaft that is rotated by a motor and to which the cutting tool is mounted. This seeks to advantageously ensure that the visual warning is in sufficiently close proximity to cutting edge(s) so that the operating cutting edge(s) do not go unnoticed.
In accordance with one aspect of the present invention, at least one of the colored portions includes indicia that moves along the path of the visual warning while the cutting tool is rotated. The indicia is readily discernable while the cutting tool is not rotated, and the indicia is not readily discernable while the cutting tool is rotated at greater than the predetermined speed. Accordingly, the indicia can provide an enhanced indication that the cutting tool is not rotating.
Thus, the present invention provides a cutting tool with an improved visual warning that primarily becomes apparent when the tool is being operated and that is preferably in close proximity to one or more cutting edges of the tool.